The present invention relates generally to transmitting equipment, and more particularly to a TACAN beacon. Various constructions of beacons used in radio navigation are already known. So, for instance, one such construction is disclosed in German Pat. No. 27 15 383. This beacon comprises a transmitter and an antenna consisting of a plurality of radiating elements arranged on a circle. Pulse-modulated radio-frequency signals generated in the transmitter are fed to the radiating elements through a power-distribution and phase-shift network that generates different radio-frequency phase-rotation fields under the control of a control facility. It is also stated there that the principle underlying the described VOR can also be used for implementing a TACAN beacon. It is well known that, in a TACAN beacon, the radiated signals consist of a carrier signal, a 15-Hz coarse bearing signal, and a 135-Hz fine bearing signal. There it is stated that the principle underlying the VOR described can also be used for implementing a TACAN beacon.
In the case of the known TACAN beacon, the upper and lower 15-Hz sideband signals of the carrier and the upper and lower 135-Hz sideband signals of the carrier are simultaneously present in space as the 15-Hz coarse bearing and 135-Hz fine bearing signals. If the principle of radio-frequency phase-rotation fields is to be used for such a TACAN beacon, an antenna consisting of at least 27 to 36 radiating elements is necessary, because a mode spread (difference between the ordinal numbers of the absolute value of the radio-frequency phase-rotation fields) of 18 is required to generate the 135-Hz sideband signals; the largest ordinal number is thus .gtoreq..vertline.9.vertline..